1. Technical Field
This invention relates to mobility services provided to mobile computer users.
2. Related Art
The use of hand held and laptop devices for computing has proliferated in recent years. Computer users retrieve electronic mail and files from distant network servers, conference with fixed or mobile conferees, and use mobile applications for sales and monitoring of inventory, shipping and receiving. In mobile computing applications, computer users move temporarily from their home networks to foreign networks. Networks route data to users through use of Internet Protocol (IP) network addresses. When users move from one network to another frequently, the routing of data to the users becomes problematic.
Mobile IP support techniques are known per se. For example, the Internet Engineering Task Force (xe2x80x9cIETFxe2x80x9d) has developed a mobile support standard that facilitates communications in a mobile environment. However, the standard has limited utility. First, existing mobility support protocols waste resources of the computer networks that route data to mobile hosts. Typically, data to be sent to a mobile host is addressed to a xe2x80x9chome agent,xe2x80x9d a computer in the host""s home network that provides mobility support to the mobile host. The data is routed through the network to the home agent. Upon receipt of data intended for the mobile host, the home agent retransmits the data though the network to a foreign agent at the mobile host""s true location. Thus, two transmissions of data are required to get the data to a traveling mobile host. Such xe2x80x9ctwo stepxe2x80x9d mobility support schemes reduce the capacity of the networks that carry data on behalf of the mobile hosts because the data travels through a non-optimal path. Further, existing mobility support protocols typically provide a home address for a mobile host that identifies a home network where the mobile host resides when it is not moving in a manner that does not maintain privacy.
Accordingly, there is a need in the art for a mobility support that provides enhanced privacy features to mobile hosts and that conserves resources of the networks that carry data to mobile hosts.
The present invention provides a mobility support technique, called the virtual mobile IP (xe2x80x9cVMIxe2x80x9d) protocol. According to this invention, home agents and foreign agents are located in mobility aware access networks. Participating mobile hosts are assigned a xe2x80x9cvirtual home address.xe2x80x9d The virtual home address is actually an address of the home agent located in the mobility aware access network. The home address provides additional privacy to the mobile host because it does not identify the mobile host""s home premises network.
By providing home agents and foreign agents in a mobility aware access network, the agents may cooperatively establish optimal routing paths for data transmitted to a mobile host. The agents may identify a pseudo home agent, an agent in a mobility aware access network located near to a transmitting mobile host, that acts as the home agent of a destination mobile host. The pseudo home agent tunnels data directly to the destination mobile host without requiring the data to be routed first to the true home agent. In this regard, the pseudo home agent establishes a more direct routing path between the transmitting and destination mobile hosts.